I need a bit of extra range when on longer rides. I am considering one of the following tool batteries. All are 40 volts and would give me the required extra range. The manufacturer's charger would be used. When needed, the ebikes regular battery would be unplugged and the tool battery plugged into the controller.

Safety is the most important feature. Can I assume they all have appropriate electronics in the battery to shut it down when the low voltage is reached? I am concerned the low voltage shut down electronics may be in the associated tool, rather than the battery.

So those packs are 20 cell packs in 10s2p configuration. I would consider what actual 18650s would cost you, and what current you can expect to get out of those 2p packs before making a purchase. the DCB407 is $289.00 on amazon prime, I just ordered a bunch of batteries and I could do almost twice the battery for what those cost.

Last edited by footbaldd on Mar 10, 2018 12:04 pm, edited 1 time in total.

Need to know more. More. It would help if we knew your motor and controller your weight and Terrain. As if you buy a battery you want to last I like your little warranty things if the warranty is valid at the store or you have to send you the end it evaluated and weight in on ect like what is the policy for exchanging the battery and warranty. Don't get me wrong if they will warranty the battery and replace it without having to buy a second battery to use before they replace it xcetera. Did I say I do like a warranty as batteries in this day in age have few.

My wife and I are retired and go on bike rides about 15 miles long at about 10-12 mph. We just enjoy a slow ride on blacktop bike paths. [...] we are both having difficulty on hills or against strong winds, we only need help in those situations.

This spring I decided to make our two old hybrid Giant 700c bikes into ebikes. I bought 36V 260 (low) rpm front geared wheels from Ebikeling and initially powered each bike with three 12v 9ah SLA batteries in series. We wanted to see how these inexpensive SLA batteries would perform for us as we live on the top of a big 3/4 mile hill. After running out of power several times while coming home from 15-20 mile rides, we upgraded to the safe 12v 10ah LiFePO4 Dakota Lithium batteries with BMS. Keeping the ebikes safe and simple was a top priority. We just plug in inexpensive 36v 1.5ah chargers after each ride. They automatically turn off after the batteries are charged. http://www.amazon.com/gp/product/B00U2Y ... detailpage

[...] Now our typical ride is 15-30 miles at a “smelling the roses” speed of 10-12 mph. We do pedal almost all of the time but need assistance on any hill or against the wind.

I'm not sure about tool packs having low voltage cutoff built in. When Syonyk wrote about tearing down a Dewalt 20V 6Ah pack, he said there was none.

Internals and Interface Board
These packs contain an interface board that serves to connect the cells to the outside world. The board has the ID resistor and thermistor as well, but it is by no means a battery management system - it doesn't appear to do any balancing, and is quite simple. There's also no low voltage cutoff or overcurrent cutoff - the tool is required to handle all that.

This means that if you want to use these packs in another project, it's really easy! Just shove some terminals in and don't be stupid about your low voltage cutoff (15V is a good idea).

DeWalt DCB407 battery clears 10 miles in human transport,
Submitted by trx430ex on February 25, 2017

Trek pure trike powered by Crystalite motor in 36volt has just traveled from the campground on Jekyll island all the way to the Westin hotel 9 miles, (lunch) then south to the new youth center. with girlfriend on back a six PAC of Corona lite, (for later) goldfish and a salad we switched to #2 batt of three and went from the youth center access all the way to northern fishing pier 14 miles on the beach.
2 weddings, 1000 beach goers and a flat front drive tire in the last 5% of the ride, switching to 3rd batt to go home.almost 26 miles in one day,@ 300 pounds ~ 2 souls'200/100 in open air.
Has anyone gone any farther?

We do run lights on our ebikes all the time and if we would forget to turn off the main power switch the battery could be drained down to 0 volts without some kind of LVC protection. There is also the slim chance of a short in the connectors/wires which could also drain the battery.

After further reading on the links provided here and also looking at other places, I think I will be going with the Greenworks battery. Breakdowns of some Dewalt batteries shows they have hardly any safety LVC electronics (probably in their tools). The Ryobi and Greenworks batteries do appear to have substantial electronics hopefully protecting the battery. The Greenworks gets better reviews than the Ryobi, plus I can use more of their tools.

I have used the Dewalt 20v max 10 cell packs (5s2p). I know cell balancing and HVC are done in the charger. I could not say about LVC. I haven't needed to rebuild one yet. It does have a three led voltage indication on the back of the pack, but I would assume that low pack voltage at the speed controller is what triggers the low voltage cutoff.

I have the 180WH (5AH) and the 80WH (probably 2AH) Ryobi "40V" batteries. Small world. My first ebike uses a 36V 500W ebikeling geared rear motor and 22A controller. I would estimate my range at 12 miles for the 180WH model on that bike. I have gone as far as 20 miles. I believe these packs do have LVC circuits, but they will shut down at half capacity, around 36 volts, as any appreciable current creates enough voltage sag to shut off the battery.

Still, the Ryobi's are somewhat adequate for smaller motors. My ebikeling kit only uses between 6-10 WH/mile in PAS level 1 at 12 mph. They're not cost effective though. I already had a Ryobi weedwhacker with the 80WH battery and charger, about 4-5 years old. The 180WH battery cost me $120 at Home Depot. If you had to buy a charger, now you're looking at $180.

I can buy a small ebike battery with twice the capacity for not much more money, or if I want to live dangerously, I can use my $35 36V 4AH hoverboard batteries. I keep the latter in an ammo can and only charge them outside, or inside a barbeque grille.

Speaking of low voltage, my ridgid batteries cut out at 12v(2.4v per cell), granted this was under no load just spinning the tool, still seems somewhat low. But the charger brings them back to life every time.

5/8/18 update...
My wife and I have been using the Greenworks 40V 5.0 Ah Lithium-Ion batteries on our ebikes and so far, are very pleased with its performance for reserve power. It does have LVC protection built into the battery and an automatic maintenance mode when not used for a month to extend the battery life. My primary concern is safety and I think it is a very safe battery to use on an ebike and charge in the garage.

Some of the advantages...
Amazon Prime shipped the batteries and charger free to my house in 1 day.
Amazon 30 day free returns.
Greenworks 2-year warranty on the battery, 3 years on the charger.
Very convenient to use on the ebike with Ordertree battery holder and insert block.
2 hour charge time.
The batteries can also be used in Greenworks lawn mowers and many yard tools.
Reasonably priced when on sale at Amazon.

We can go about 15 miles on the Greenworks 5ah battery alone, plus go up a very big hill. Our travel speed is about 10-12 mph on paved bike trails with our city bikes and we almost always lightly pedal along for the exercise (we are 74 years young). The batteries have given us the reserve power needed in additions to our 40v 10ah primary batteries. Just a flick of a switch will select either the primary or reserve battery.

When our primary batteries start to deteriorate I plan to totally power each ebike with 2 or 3 Greenworks batteries.

I have the 180WH (5AH) and the 80WH (probably 2AH) Ryobi "40V" batteries. Small world. My first ebike uses a 36V 500W ebikeling geared rear motor and 22A controller. I would estimate my range at 12 miles for the 180WH model on that bike. I have gone as far as 20 miles. I believe these packs do have LVC circuits, but they will shut down at half capacity, around 36 volts, as any appreciable current creates enough voltage sag to shut off the battery.

Still, the Ryobi's are somewhat adequate for smaller motors. My ebikeling kit only uses between 6-10 WH/mile in PAS level 1 at 12 mph. They're not cost effective though. I already had a Ryobi weedwhacker with the 80WH battery and charger, about 4-5 years old. The 180WH battery cost me $120 at Home Depot. If you had to buy a charger, now you're looking at $180.

I can buy a small ebike battery with twice the capacity for not much more money, or if I want to live dangerously, I can use my $35 36V 4AH hoverboard batteries. I keep the latter in an ammo can and only charge them outside, or inside a barbeque grille.

I loved these hover board batts but i have been stalking them lately and the price has gone up. Cheapest around are $50 each and most are generic cells

I have been using Bosch bat 838 36v@4A.for 3 years . I charge them to 40.7V to extend the cycle life. You can use any suitable charger by connecting +,- on the battery terminal which is marked. I am using 2 groups of 3x36v4a = 36 v@12a each. I am running a 72v system on 9C rear pulling 3000 watts with very little sag. The battery sells for about 150.00 US.

I asked Grenworks customer service if their 40v Gmax batteries had low voltage protections. Their answer...

Yes the 40V GMAX batteries have a low voltage protection built into them.

Has this been verified? Customer service doesn't always give the answer that we need for DIY re-purposing. Often the LVC is provided by the tool rather than the battery, or by a combination of the BMS in the battery communicating with the tool. So from their perspective it is there, but if you re-purpose them into an ebike their answer may not apply.

Regarding low voltage protection, that would only work on batteries where the power flows through mofets. What I'm seeing in many newer batteries is they don't send the power through mosfets (this increases resistance and voltage loss) but instead rely on the tool to sense when the battery is low and to stop drawing power from the motor controller. The porter cable, snap on and dewalt batteries I've opened lately all do not have power mosfets but work this way. The old porter cable 18v battery has a large mosfet where the full power that the tool needs flows through it.

Putting power MOSFETS in the battery is not only an extra cost for the battery, and an additional power loss, it is redundant because the tool must have MOSFETS to control the motor (in the tool) anyway. So from a systems engineering standpoint it makes more sense to communicate to the tool when LVC is approached and allow the controls in the tool to take action to protect the battery in a more tool-sensible way. For example in the EGO blower the TURBO function may be disabled while the blower may continue to operate at regular speeds.

The sizing of FETs in the battery is problematic, but in the tool the actual current needs of the motor are known, so the FETs can be appropriately sized. There is also funding in the tool for this, while adding the maximum current ever to be encountered FETs to every battery pack drives the battery cost up for no reason. In any case it is redundant so is not a good return on investment.

The EGO battery packs are very well engineered with respect to cooling and temperature control (many include phase change materials), and they have an extensive BMS which communicates with the tool and charger. There are no FET switches between the cells and the output power contacts.